A trend in the semiconductor manufacturing industry is to integrate different circuit elements, including logic, memory, processors, peripherals, etc., on a common semiconductor substrate. Such integration can lower manufacturing costs, simplify manufacturing procedures, and increase operational speed of the resultant circuit compared to approaches where the circuit elements are made on separate ICs and then electrically coupled to one another on a printed circuit board. One type of integrated device is an embedded flash memory device. An embedded flash memory device can include an array of flash memory cells and logic circuits that support operation of the flash memory cells, and can optionally include processors, peripherals, and the like.
One type of flash memory cell that can be used in embedded flash devices is a split-gate flash memory cell, such as a third generation SUPERFLASH (ESF3) memory cell. Compared to earlier generations of flash memory cells, split-gate flash memory cells have lower power consumption, higher injection efficiency, less susceptibility to short channel effects, and over erase immunity. As such, split-gate flash memory cells are becoming more prevalent in today's memory and embedded products.